# Parse the `input` string as a MdDocument
	fun parse(input: String): MdDocument do
		initialize

		var document_block_parser = new MdDocumentBlockParser(1, 1, 0)
		activate_block_parser(document_block_parser)
		var line_start = 0
		var line_break = find_line_break(input, line_start)
		while line_break != -1 do
			var line_string = input.substring(line_start, line_break - line_start)
			incorporate_line(line_string)
			if line_break + 1 < input.length and
			   input.chars[line_break] == '\r' and
			   input.chars[line_break + 1] == '\n' then
				line_start = line_break + 2
			else
				line_start = line_break + 1
			end
			line_break = find_line_break(input, line_start)
			line += 1
			column = 0
		end

		# Finalize pending line
		if input.length > 0 and (line_start == 0 or line_start < input.length) then
			incorporate_line(input.substring(line_start, input.length - line_start))
		end
		finalize_blocks(active_block_parsers)

		# Walk through a block and its chiildren revursively
		# Parsing string content into inline content where appropriate.
		var all_block_parsers = all_block_parsers.to_a
		var i = all_block_parsers.length - 1
		while i >= 0 do
			var block_parser = all_block_parsers[i]
			block_parser.parse_inlines(inline_parser)
			i -= 1
		end
		var document = document_block_parser.block
		return document
	end